The availability of an effective, reliable and accurate means for calibrating digital torque tools is one of the key factors for insuring digital torque tools to be used in more and more popularized in the years to come. Taking a digital torque wrench for instance, its precision specification is usually defined as ±1˜5%, but the reliably of such precision can varied or deteriorated during the extended usage of the digital torque wrench, so that it is required to be calibrated for insuring the same to function effectively and accurately within the range of its precision specification. It is noted that the difference between a digital torque wrench and a mechanical torque wrench is that: the digital torque wrench is equipped with an electronic means for accurately measuring and displaying the amount of torque applied thereby.
Conventionally, the devices for calibrating digital torque wrenches can be divided into two types, which are the automatic torque testers and the torque balance testers. Operationally, the automatic torque tester will use a driving motor to exert a varying force upon a digital torque wrench that is to be calibrated, causing the torque meter of the test and the sensor of the digital torque wrench to issue signals in response to the varying force to a processing unit of the tester, in which the characteristic curve corresponding to the signals from the sensor of the digital torque wrench is compared with a standard stain curve of the torque meter that is registered in the processing unit for allowing the standard stain curve to overwrite the characteristic curve corresponding to the signals and thus to be registered into the memory of the digital torque wrench, and thereby, calibrating the characteristic curve of the digital torque wrench to match exactly with the standard stain curve of the torque meter. On the other hand, the torque balance tester will compare the torque value displayed on a digital torque wrench that is to be calibrated with a standard torque value obtained from the torque balance tester so as to obtain an error value for the digital torque wrench, but without calibrating data registered in the memory of the digital torque wrench according to the error value. However, no matter the calibration is performed by the automatic torque testers or by the torque balance testers, the procedure for calibrating a digital torque wrench typically requires that the tool be sent to a facility that specializes in digital torque wrench calibration. The time that is required to calibrate the digital torque wrench can significantly vary, which can take two to four weeks depending on the size and capabilities of the calibration facility, and the owner of the digital torque wrench is usually required to pay for the shipping of the tool or tools both ways as well as the calibration fee.
There are already many studies for improving the aforesaid disadvantages regarding to the calibrating of digital torque tools. One of which is a torque wrench with wireless communication ability, disclosed in TW Pat. No. M381484, in which the two-way wireless communication between the torque processing circuit of at least one torque wrench and a controller is enabled for allowing the controller to receive remotely and simultaneously the information relating to the torque value of the at least one torque wrench that is issued from the corresponding torque processing circuit. Thereby, since the controller is further being connected to an electronic calculation device, such as a personal computer (PC), a personal digital assistant (PDA), or a notebook computer, in a wireless or wired manner, the torque output of the at least one torque wrench can be processed and managed by the electronic calculation device, i.e. the operation of the at least one torque wrench can be controlled by the electronic calculation device. However, although the operation of each torque wrench is controlled and managed by the electronic calculation device in a wireless manner, there is no embodiment in the aforesaid disclosure describing how to calibrate the torque wrenches that are wirelessly connected to the electronic calculation device.
Another such study is an intelligent control system for torque tester and the torque testing method used thereby, disclosed in TW Pat. No. 201022651, in which the intelligent control system is adapted specially for controlling a torque tester and provides a human interface that is designed aiming for minimizing the repetition of parameter input and thus reducing the happening of human error so as to speed up the operation of the torque tester. Operationally, the intelligent control system, that is operated by a user, is enabled to connected remotely through Internet with a diagnosis module located in the facility specializing in digital torque tool calibration, and thus either the user is able to select options of diagnosis displayed on the human interface that are transmitted remotely from the diagnosis module for calibrating the torque tester, or an operator of the diagnosis module is able to calibrate the torque tester remotely through the connection between the diagnosis module and the human interface of the intelligent control system. However, the aforesaid remote communication is used for calibrating torque testers, but not designed for calibrating torque tools, not to mention that there is no method and procedure being embodied in the aforesaid disclosure describing how to calibrate torque tools.
Further another such study is an electronic torque-tool tester disclosed in U.S. Pat. No. 7,222,544, in which the electronic torque-tool tester is characterized in that: it is configured with a digital display unit to be used for displaying a torque applied by a torque tool in a real time manner as the detection of the torque is digitized by a microprocessor. However, there is no method and procedure being embodied in the aforesaid disclosure describing how to calibrate torque tools.